SOLUTION: the intensity of light (in foot-candles) varies inversely as the square of x, the distance in feet from the light source. the intensity of light 2 feet from the source is 10 foot-c

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Question 890614: the intensity of light (in foot-candles) varies inversely as the square of x, the distance in feet from the light source. the intensity of light 2 feet from the source is 10 foot-candles. How far away is the source if the intensity of light is 2 foot-candles?
Answer by lwsshak3(11628) About Me  (Show Source):
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the intensity of light (in foot-candles) varies inversely as the square of x, the distance in feet from the light source. the intensity of light 2 feet from the source is 10 foot-candles. How far away is the source if the intensity of light is 2 foot-candles?
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let x=distance from source
(x/2)^2*2=10
x^2/4=5
x^2=20
x=√20=2√5
How far away is the source? 2√5 ft